MOSCOW: Moscow vowed Thursday to respond in kind to "unfriendly" European Union sanctions imposed over Russia's invasion of Ukraine.

"In accordance with the principle of reciprocity, which is fundamental to international law, we will take tough retaliatory measures," the foreign ministry said in a statement.

"The EU's new unfriendly steps against Russia -- as well as our brothers DNR and LNR -- will not be able to stop our progressive development," the foreign ministry said, referring to Ukraine's separatist regions.

US, G7 allies ready response to Russia's attack on Ukraine: Biden

The West has said it is preparing unprecedented sanctions against Russia after President Vladimir Putin launched an invasion against Ukraine, despite threats of sweeping economic penalties from Washington and the European Union.

The United States declared the Kremlin's prize energy project, Nord Stream 2, dead this week as Russia sent troops to eastern Ukrainian breakaway regions, the so-called Donetsk People's Republic and Lugansk People's Republic.